1156985781 has 8 divisors (see below), whose sum is σ = 1763025984. Its totient is φ = 661134720.

The previous prime is 1156985773. The next prime is 1156985789. The reversal of 1156985781 is 1875896511.

It is an interprime number because it is at equal distance from previous prime (1156985773) and next prime (1156985789).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1156985781 - 2³ = 1156985773 is a prime.

It is a super-2 number, since 2×1156985781² = 2677232194872359922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1156985789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27547260 + ... + 27547301.

It is an arithmetic number, because the mean of its divisors is an integer number (220378248).

Almost surely, 2^1156985781 is an apocalyptic number.

It is an amenable number.

1156985781 is a deficient number, since it is larger than the sum of its proper divisors (606040203).

1156985781 is an equidigital number, since it uses as much as digits as its factorization.

1156985781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55094571.

The product of its digits is 604800, while the sum is 51.

The square root of 1156985781 is about 34014.4936901904. The cubic root of 1156985781 is about 1049.8067009249.

It can be divided in two parts, 115 and 6985781, that added together give a palindrome (6985896).

The spelling of 1156985781 in words is "one billion, one hundred fifty-six million, nine hundred eighty-five thousand, seven hundred eighty-one".